When his soccer career ends Thursday night at the National Sports Center in Blaine, Kyle Altman figures to leave the field feeling both regret and reborn.

The three-time captain of Minnesota United FC, considered one of the top central defenders in the North American Soccer League, never reached his goal of playing Major League Soccer, something his teammates find bewildering. But he is following a greater calling now, one he postponed for three years and could no longer put off.

Altman is going to medical school.

A white-coat ceremony will officially begin the 27-year-old’s journey on July 21 at the University of Texas Health Science Center’s School of Medicine in San Antonio. Where it ends, Altman is unsure. His father, Alan, is an orthopedic surgeon specializing in bones and joints. Altman hopes to become a surgeon of some sort because he values interacting with people.

Choosing a specific medical discipline, which Altman said will take place in his “third or fourth year” of medical school, should be a less arduous decision than the one to give up soccer.

“You don’t control what opportunities you have, but you can control what you do with the ones you have,” said Altman, referring to medical school. “I feel like I’d be doing a disservice to myself to not take advantage.”

Quest for epiphany moments

Altman, a native of Albuquerque, N.M., grew up being taught the values of education, one reason he said he chose Trinity University in San Antonio. The campus sits about 8 miles south of where he will attend medical school.

Soccer came first, however, when New England selected Altman in the 2008 MLS supplemental draft. He left Trinity, where he played with older brother Kelly and was a two-time NCAA Division III All-America, one semester shy of graduating.

Unable to crack New England’s roster, Altman joined the Minnesota Thunder. In 2009 he sat out the season and completed his undergraduate degree in economics with a minor in chemistry while doing pre-med coursework.

A strong science interest runs through the Altman family. His mother, Kathy, was involved in marine biology before she had three sons. His oldest brother, Ryan, is an assistant professor of medicinal chemistry at the University of Kansas.

“I’ve always been interested in the way things function; not how things happen, but why,” Altman said. “I love that epiphany moment when you realize why something is the way it is.”

‘Don’t bother asking’

Accepted to medical school in 2010, Altman asked for a one-year deferment while he restarted his soccer career. He made similar requests in 2011, before leading the then Minnesota Stars to the NASL championship, and again in 2012, when the Stars returned to the finals and he was named to the league’s Best XI team.

Students are granted deferments, Altman said, to pursue “real-world experiences” or to “get their finances in order.” Second deferments are unusual, third deferments rarer still.

“I got an e-mail from one of the doctors that said, ‘Don’t bother asking for a fourth,’ ” Altman said.

The penalty for a fourth postponement, Altman said, would have been the time and expense involved in retaking much of his coursework and reapplying for admission to medical school.

Nevertheless, he tried out earlier this year with Portland and D.C. United, two MLS teams. Making either squad would have put medical school on indefinite hold, a sacrifice Altman said he would have made “because it’s a dream.”

“Playing MLS is a big attraction, especially when you’ve come as far as I have,” Altman said. “So it was probably ego more than anything else.”

Staying sharp on, off the field

Has the decision to trade his captain’s armband for a white coat brought Altman peace?

“Hard to say,” Altman said. “Sometimes more than others. I feel like I’m walking away when I’m playing my best soccer. I could have a longer career, most likely here in Minnesota.”

United goalkeeper Matt VanOekel, who started in Minnesota with Altman in 2008, understands his friend’s reluctance to retire.

“I think it’s tough for him to hang it up because he sees guys he played with going to MLS,” said VanOekel, who spent a month training with D.C. United of MLS earlier this year. “Many of us think he could play at that level.”

Taking a rational view, Altman knows going to medical school puts him on a more lucrative post-soccer path than many peers are on. Leaving professional soccer, Altman said, “is a tough transition for a lot of guys because they have to learn who they are without their main identity.”

VanOekel knew one player from D.C. United going to medical school but said “a lot of guys” playing various levels of pro soccer “haven’t finished college.”

“It certainly is rare,” Minnesota United coach Manny Lagos said of Altman’s medical school pursuits. “And it doesn’t surprise me that Kyle stayed so committed to soccer while working on his next path.”

To keep his mind sharp, Altman took online courses in biochemistry and genetics through the University of California-Berkeley. He is currently taking two more, the biology of cancer and human anatomy. But he does not earn credits toward medical school for any of them.

Likewise, a victory in Thursday’s game against Atlanta would have no bearing on Minnesota’s playoff chances. After its latest loss, the team cannot win the spring season title anymore for a spot in November’s finals. The next chance will come with the season’s second leg, which starts in August.

By then Altman will be gone. But his pending retirement gives teammates something extra to strive for Thursday.

“I’d be shocked if anyone who stepped on the field was not thinking about winning for Kyle,” teammate and housemate Travis Wall said. “He represents everything you want in a captain, and we want to see him go out the right way.”